I played around with this a bit, and this is how it seemed to work for me:

Once you modify and save the recipe (saving is crucial), the shopping list should change. If you still have the original recipe in the Planned Recipes folder, you'll need to delete the recipe from that folder to remove the ingredient from the shopping list. Or you could set the planned number to '0', after which the ingredient won't disappear, but the quantity will be set to '0'.

derfburg21 wrote:So if I have 10lbs of 2-row in the in My Ingredients", and I have a recipe that calls for 2lbs, then "My Ingredients" would show that I had 8lbs left after I delete it from "Planned recipes" section.

You would need to hit the 'deduct' button to get BTP to subtract the ingredients from your inventory.

From your screen shot, EKG is the only ingredient in your recipes that is in your inventory folder. It's listing that you need to buy the other ingredients.